Polymer Engineering

polymer

a large molecule composed of repeating structure units, connected by covalent bonds

homopolymer

a polymer with only one type of repeating unit

copolymer

a polymer with two or more types of repeating units

What kinds of copolymers are these?

statistical/random, alternating, block, graft

monomer

a small molecule with 2+ bonding sites used to form polymers

monomers are the same as repeating units (T/F)

false- they are the same in chain/addition synthesis, but not in step-growth synthesis

types of polymer synthesis

step-growth and chain/addition

step-growth synthesis

polymers are formed from a succession of condensation reactions, occurs in monomers with functional groups like -OH and -NH2

chain/addition synthesis

polymers are formed by the stimulated opening of a double bonding with a free radical or ionic initiator, occurs in olefinic monomers with double bonds

number average molar weight equation

Mn = sum(NM)/sum(N)

weight average molar weight equation

Mw = sum(WM)/sum(W) = sum(NM^2)/sum(NM)

polydispersity index (PDI) equation

Mw/Mn

monodisperse

PDI = 1

usually, PDI > 1

true